Fabrizio Carbone discusses how Ultrashort pulses of X-rays from a free-electron laser capture the spatiotemporal evolution of spins in the different crystallographic directions of a complex magnetic material.

Diffraction and spectroscopy are the most common methods in condensed-matter physics research, but they provide information in the reciprocal space. Going back to real space and real time, where our own senses and intuition function, is a challenge that we are currently addressing through different microscopy and time-resolved methods. Whereas atomic and femtosecond resolutions have been available for a long time, their combination is not straightforward. In addition, the physics of materials is ruled by the position of atoms and the distribution of charges and spins around them, and these three observables have very different cross-sections and interaction mechanisms when studied with probes such as photons of different wavelengths, electrons, positrons, muons or neutrons. Studying magnetism — originating from the concerted alignment and motion of spins — using real-space and real-time techniques currently poses one of the toughest experimental challenges.